The K&F D-Series UV Filter is a well-made, durable optical device that appears to perform as advertised. I wish I had noticed that the NANO series filters are a little better and only a little more expensive. In any case, if you compare this D series filter directly to the B&W UV Protection Filter (010) (XS-PRO), MRC Nano, the K&F product seems to be of the same quality and performance for less than half the price .

Arrived quickly. It was exactly as expected, fitted the camera perfectly and was easy to install. Lens hood and cap both fit as before. Ideal for Panasonic DMC FZ2000

Arrived quickly. It was exactly as expected, fit the camera perfectly, and was easy to install. Lens hood and cap both fit as before. Ideal for Panasonic DMC FZ2000

Personally, I don't like using UV protection as it can distort/defocus image quality.
I invested a lot in my lens and went for more expensive ones like this one.
I don't see any reduced image quality or focus speed degradation.
Good protection / fit.

Highly recommended

Got some new RF lenses, needed the 43mil and here we go.

Great fit, doesn't interfere with retracting the R's Ben when shutting down, nice protection at a good price.

I just got a new lens, needed a 77mm filter to protect it. I'm not going to sit down and tell you that this glass is better than any other glass. I just got it and I'm not an optics expert.
But I can tell you the packaging was beautiful, the filter housing - one of the nicest I've ever seen. It is circular in shape and holds filters of multiple sizes with grooves in an internal holder. So much nicer than the big chunky square filter boxes I have from other brands.
But - the killer was the filter which was so thin - and that it has 2 areas that are knobby so you can grab it - while the rest is smooth - a really nice feature.
Seems right at home on my Canon RF24-105/4 L IS USM.
I didn't notice any difference in focus speed or aberration, but again, I'm not a lab.
I'm pretty happy with this brand. I did not expect.

I had previously used a common UV filter. It's not bad. Only under certain conditions would glare or aberration occur. For the most part it worked fine. But it still annoyed me. So I ordered this K&F UV filter. WOW! What a difference! The glass is so clear you can't tell it's in the case! And that's how clear my photos became with it! Definitely worth the price difference! All my filters are now K&F brand. The quality is excellent!

With this review I am referring to the product "K&F Concept Nano X-Series UV Filter 82mm Schott-Glas B270 28 Layers MC Super Slim", which I purchased in January 2023 and now after a few weeks I would like to share my experience.

Background:
As should already be generally known, UV filters are no longer bought for UV protection these days, since no damage from UV radiation is to be expected due to various lens coatings. The UV filters are therefore usually only used as lens protection to protect the front element of an expensive lens against dirt and damage. In the event of damage, it can simply be replaced.
I therefore primarily wanted protection for my Sigma 24-70mm 2.8 Art and my Sigma 35mm 1.2 Art, which have the same filter diameter.

Positive:
I could not detect any noticeable change in image quality in my tests. Both the sharpness in my test photos was the same as without a filter and I could not see any artefacts or disturbing light reflections. There are also several independent tests that compare the quality of UV filters - the K&F Nano-X does not show any major loss of quality, at least not in these either.
The ribbing on the outside of the filter is also very positive. This is (at least subjectively for me) actually helpful and creates more grip.
The box is also stable enough to safely take the filter with you to the place of use.

Neutral:
What is also often criticized with cheaper filters is the canting of the filter, which means that it can no longer be loosened. With my copy I could see differences between my lenses, but the filter always ran quite smoothly. At least I couldn't find any major problems. As you can hear in the attached video, it makes noises on my 35mm 1.2, but doesn't tilt at all.

Negative:
I didn't notice any points that would make me devalue the full number of points differently.

If this review and the attached pictures and videos were helpful, I would be happy to receive positive feedback ("helpful answer" button). If you have any questions, please leave them on the product page. I'll try to answer them there too!

I mainly use it to protect my lens from scratches and dirt.
It reduces the amount of ultraviolet light entering a camera.
Without this filter you will notice discolouration.
It effectively removes the appearance of blue tones bleeding in your photos.

I'm old school: I always put a UV filter on my lenses to protect the front element. If you want to know how valuable that is, just look at how far fewer lenses that have "just a little scratch" on the glass are being sold on FB Marketplace or eBay - in fact most people just would don't buy anything.

All in all, it's a no brainer for the price.

Being primarily a wildlife photographer, dust is more of an issue; I'd much rather dust off a cheap (similar) UV filter than possibly scratch the coatings on my expensive lens.

I didn't notice it with this lens, but most UV lenses tend to add the slightest, almost insignificant, blue cast to any image. Since I would process each shot I consider them decent and "worth it" in Lightroom anyway,

it's worth it.